The invention relates to a vehicle theft detection device for determining whether or not a theft occurs using information from an inclination sensor for detecting inclination of the vehicle or the like and generating an alarm if a theft occurs or if there is a possibility that a theft may occur.
Upon detection of unauthorized door opening, breaking into the vehicle interior, inclination of the vehicle, unauthorized invasion of glass breakage, etc., or its preliminary action during arming (lookout), the vehicle theft detection device generates an alarm or reports occurrence of the unauthorized invasion to a predetermined location in a wireless manner; it is widely commercially practical at present.
The inclination sensor system for detecting inclination of the vehicle uses the fact that the vehicle is unnaturally inclined if an attempt is made to steal a tire or a wheel or the vehicle itself using a jack or a wrecker; if an abnormal inclination occurs, the inclination sensor system actuates an alarm, etc.
To determine the inclination degree of the vehicle, an acceleration sensor is installed in the vehicle. Using the values of the inclination angle and the angular velocity or the signals provided by filtering the values, the difference between the initial inclination angle at the parking start time and the later inclination angle is adopted as a determination index and a comparison is made between the found inclination angle and a predetermined theft detection threshold value, whereby a theft determination is made, as shown in FIG. 20.
On the other hand, if the vehicle is parked in a tower parking lot, the vehicle may sway or may be inclined as a palette in the parking lot moves when the vehicle is put in or goes out of the parking lot; if the vehicle is put on a ferry, the vehicle may be inclined as the ferry sways. Therefore, the inclination sensor system makes an erroneous determination and actuates the alarm; this is a problem. Thus, a system wherein a vehicle theft detection device is provided with a switch for turning of theft detection based on inclination and a multistory parking mode is proposed for the purpose of turning off the function of the inclination sensor in the situation where a vehicle will sway at the parking time, as in a ferry or a tower parking lot (for example, JP 2003-34233 A).
In the foregoing examples, all of the related arts and limitations related thereto are intended to be illustrative and not exclusive. Other limitations of the related arts will become apparent to those skilled in the art on a reading of the specification and a study of the drawings.